Packet scheduling system for digital video broadcasting
AssigneeTandberg Television Inc.
InventorXiaoguang Li
Life of this patent
Estimating the term…
Abstract
A system and method for processing multiple client flows to a single outbound link is provided. Specifically, a scheduler enforces a maximum symbol rate on the aggregate output flow. Inbound client flows are scheduled for output based upon individual quality of service parameters. For each round of scheduling, packets configured for a first bandwidth range are processed in a first pass and packets configured for a second bandwidth range are processed in a second pass. The packets are placed into frames before transmission. A comparison of the actual symbol usage with the estimated symbol is made and used to determine how to schedule inbound client flows for the second pass of the round.
Claims19
A device, comprising:
- a first input buffer to store a first input stream;
- a second input buffer to store a second input stream;
- a scheduling multiplexer coupled to the first input buffer and the second input buffer to schedule a plurality of packets for transmission based upon an estimated quota of symbol consumption;
- an output buffer coupled to the scheduling multiplexer to store packets scheduled for transmission;
- and
- a framer coupled to the output buffer to generate a baseband frame and further configured to determine an actual symbol consumption based on a MODCOD for the baseband frame.
A system, comprising:
- N buffers, wherein N is an integer greater than one, wherein each of N buffers is coupled to a client to receive an input stream;
- a scheduling multiplexer coupled to N buffers configured to schedule a plurality of input stream packets for transmission to a single outbound link of a network based on an estimated symbol consumption on an outbound link during a present round;
- a packetizer coupled to the multiplexer configured to convert a plurality of input stream packets to MPEG-2 transport stream packets;
- and
- a framer coupled to the packetizer configured to place the MPEG-2 transport stream packets into one or more baseband frames (BBFRAMEs), wherein the framer determines an actual symbol consumption number for the one or more baseband frames and transmits the actual symbol consumption number to the scheduling multiplexer.
A method for scheduling input flows in a scheduling multiplexer, comprising the steps of:
- receiving a plurality of input flows at a first input buffer and a second input buffer associated with the scheduling multiplexer;
- receiving an actual symbol consumption value from a framer transmitting a first plurality of packets previously multiplexed by the scheduling multiplexer and provided to a packetizer which in turn provides the first plurality of packets to the framer;
- determining a present estimated symbol quota value in the scheduling multiplexer based comparing the actual symbol consumption value with a previous estimated symbol quota,
- wherein said present estimated symbol quota value is reduced relative to the previous estimated symbol quota if the actual symbol consumption value was greater than the previous estimated symbol quota, and
- wherein said present estimated symbol quota value is increased relative to the previous estimated symbol quota if the actual symbol consumption was less than then previous estimated symbol quota;
- and
- multiplexing a first number of bits from the first input buffer with a second number of bits from the second input buffer based on the present estimated symbol quota value.
Dependencies are inferred from the claim text.